Originally in a telecommunications network, the switching office (hereinafter switch) made all decisions on call processing features, without any need for external information, such as a database. Data, associated with a telephone call, was common to many locations, and the storage capacity of disks or random access memory (RAM) in the switch was sufficient to handle the data. Eventually, however, technological advances, information expansion, and network complexity necessitated access to external resources for assisting the switch in the call processing decisions. Intelligent Platforms (IP), such as a remotely located database, evolved and began assisting in the decisions on call processing features on a significant amount of the network traffic.
Currently, data links connect the switch and the remote database via the well-known X.25 packet-switched communications protocol, as described in U.S. Pat. Nos. 5,095,505 and 5,335,268 which are of common assignee with the present invention. The disclosures of these patents are incorporated herein by reference. The data links, for example, permit data transfer in call routing, card verification, address translation information, etc. The current architectural configuration consists of a set of 19.2Kbits/sec point-to-point links between each switch and each database. Typically, several databases, holding identical information, are attached to a single switch for creating a robust network. In this multi-database configuration, failure of a database or a data link of the database will not prevent the switch from completing the calls, as the switch will request one of the remaining databases for assistance in call processing.
To balance the volume of data transactions among the databases, a round-robin link selection algorithm is currently used by the switch. This algorithm sequentially accesses each database connected to the switch, balancing traffic among them, as well as between the links to each database, to ensure that no single link is overloaded while other links are carrying little or no data traffic.
While the round-robin link selection algorithm has an advantage of distributing the data transactions among the databases equally, it fails to consider the cost of data routing to various databases. For example, if the call, requiring special processing by the database, is originating on the East Coast of the United States, it would be more cost efficient for the long distance carrier to access the database also located on the East Coast. If, however, the round-robin link selection algorithm is used by the switch, the call-related information might have to be routed to the database on the West Coast, if according to the algorithm, it is its turn to process the call. The response from the database would have to be returned to the East Coast for completing the call. This cross-country round trip results in inefficient and expensive call processing by the long distance carrier.
The benefit of balancing the traffic by the round-robin link selection algorithm might have outweighed the routing cost while the data traffic between the switch and the database was light. As the long distance carriers constantly strive to provide more enhanced intelligent networking technologies and services, projections show that the throughput requirements will grow much faster than the processing capabilities of the network. This growth is due to the increase in traffic volume, the types of calls requiring special processing, and the number of transactions per call. In view of this significant growth, the cumulative effect of cost effectively routing data transactions becomes an important factor in the business decisions of the long distance carriers.
Intensified by the increased number and volume of data transactions between the switch and the database, a need therefore exists for cost effectively allocating traffic, associated with a telephone call, among various databases that share information resources for the switch.